Activation energy: Kickstarting chemical reactions - Vance Kite

活化能：化學反應的啟動開關 - 萬斯凱特 (Vance Kite)

Transcriber: Andrea McDonough Reviewer: Bedirhan Cinar

譯者: Jephian Lin 審譯者: Allen Li

Right now, trillions of chemical reactions

此刻有上兆個化學反應

are humming away in the cells of your body.

正在你身體細胞中進行

You never feel them,

你感覺不到

but without these reactions,

但沒有這些反應

you wouldn't be alive.

你就活不了

Unfortunately, each of those reactions needs some help.

不幸的是，每個反應都需要幫忙

You see, most molecules are stable,

大多數分子是穩定的

they are happy just the way they are.

滿足又快樂

The atoms in them are all bound-up and friendly with one another

原子融洽的靠在一起

and would prefer to stay that way.

對現況很滿足

The problem is, for a chemical reaction to happen,

問題是，要讓化學反應發生

the atoms that make up those stable molecules

穩定分子裡的原子

need to break away from their friends

就必須和朋友分開

and go buddy up with another atom.

改和其他原子搭檔

This break-up is where the molecules need a hand.

分子要分開，需要一些幫手

This initial kick-start is known as activation energy.

第一個幫手叫做「活化能」

It's used to destabilize the molecule,

用來讓分子不穩定

to push the bonds between the atoms

把原子間的鍵結推開

to a place where they are ready to break.

推到可以斷裂的程度

This unstable state is known as the molecule's transition state.

這個不穩定狀態即是 分子的「過渡狀態」

Once a transition state has been achieved,

一旦達到過渡狀態

the atoms become willing to leave their current molecular friends

原子就比較願意離開老朋友

and go make new friends elsewhere.

再去別處交新朋友

Once they are convinced, it's a piece of cake.

只要能說服，一切都簡單

Bonds break,

破壞鍵結、

atoms rearrange,

重組原子…

and the rest of the reaction happens automatically.

其他反應就會自動進行

After that first push, the body doesn't need to put in

在這第一次幫忙後，身體就不用

any more energy to help the reaction along.

投入更多的能量，協助反應進行

Left alone, most of these reactions would be very slow

若不幫忙，大部份反應都很慢

because it takes quite a while to build up

需要很長時間，才能累積到

the activation energy the molecules need to get started.

足以啟動分子的活化能

Enter the enzyme.

接著是「酵素」

Enzymes are proteins that speed up,

酵素是一種蛋白

or catalyze, reactions

可加速或催化反應

by lowering the activation energy.

方法是降低活化能

They make it easier for the molecule,

酵素能讓分子

also known as a substrate,

也就是「生物基質」 (substrate)

to get to the transition state.

更容易到達過渡狀態

You can think of a reaction like a race.

你可把反應想像成賽跑

Some racers are running along,

有些選手一個人跑

while others have teammates to help them.

有些則有隊友幫忙

Meet Sam the Substrate.

現在介紹－基質山姆

His team is the MODS Squad.

他的隊友是 MODS 小組

Together, his team is able to get to the finish faster,

團隊合作後，可以更快速、

using less energy.

用更少能量完成

There are four special enzymes in Sam's team.

山姆的小組，有四種特殊酵素

Each has a different strategy

每個策略都不同

for lowering the energy it takes to get going

但目的都是用更少能量

and speeding up the pace to get the MODS to the finish line.

幫 MODS 小組更快到達終點

The "M" stands for "microenvironment".

M 代表「微環境」 (microenvironment)

This enzyme creates a tiny, special environment for the substrate,

為基質建立一個微小的特殊環境

resulting in a faster reaction time.

以加速反應過程

He runs ahead of the pack,

他跑在最前面

flattening out bumps in the road

把路面鋪平

and misting cool water on his team of molecules.

幫隊友的分子灑水

"O" is for "orientation".

O 代表「導引」 (orientation)

Sometimes two molecules must be positioned

有時候兩個分子要反應

just right before they will react.

先得在對的位置

Like a friend at the finish line,

他就像在終點線的隊友

the O enzyme provides his molecules

他會提供他的分子，

with specially shaped spaces

會提供特殊形狀的空間

that allow the substrates to interact in just the right way.

讓基質可順利完成交互作用

"D" stands for "direct participation".

D 是指「直接參與」 (direct participation)

Every now and again, a little muscle is needed.

有時候，直接推一把

And when his teammates are struggling to finish the race,

對終點前掙扎的隊友最有幫助

Teammate D is there to pick them up

隊友 D 會把他抓起來

and carry them over the line.

帶他衝過終點線

Finally, "S" is for "straining bonds".

最後， S 是指「拉扯鍵結」 (straining bonds)

This guy pushes the team

這傢伙會強迫隊員

through some serious flexibility exercises:

認真做柔軟操

splits,

劈腿、

lunges,

弓箭步、

backbends,

下腰、

the works.

活動全身

Sometimes his substrate teammates

有時候他的基質隊友

just need to be stressed and flexed

只需一些壓力和伸展

into their transition state.

就能變成過渡狀態。

So that's it.

再複習一次：

Remember that all reactions need energy to get going.

所有反應進行，都需要能量

This energy is known as the activation energy.

稱為活化能

Enzymes lower that activation energy

酵素可降低活化能

and speed the reaction through team MODS:

MODS 幫助反應加速

microenvironment,

微環境、

orientation,

導引、

direct participation,

直接參與、

and straining bonds.

拉扯鍵結